US20140118115A1 - Protection of communication between an electromagnetic transponder and a terminal - Google Patents
Protection of communication between an electromagnetic transponder and a terminal Download PDFInfo
- Publication number
- US20140118115A1 US20140118115A1 US14/123,751 US201214123751A US2014118115A1 US 20140118115 A1 US20140118115 A1 US 20140118115A1 US 201214123751 A US201214123751 A US 201214123751A US 2014118115 A1 US2014118115 A1 US 2014118115A1
- Authority
- US
- United States
- Prior art keywords
- terminal
- transponder
- value
- current
- communication
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
- 238000004891 communication Methods 0.000 title claims abstract description 29
- 238000000034 method Methods 0.000 claims abstract description 20
- 230000005540 biological transmission Effects 0.000 claims abstract description 10
- 230000008878 coupling Effects 0.000 description 45
- 238000010168 coupling process Methods 0.000 description 45
- 238000005859 coupling reaction Methods 0.000 description 45
- 238000005259 measurement Methods 0.000 description 21
- 230000033228 biological regulation Effects 0.000 description 7
- 238000010586 diagram Methods 0.000 description 6
- 230000004048 modification Effects 0.000 description 6
- 238000012986 modification Methods 0.000 description 6
- 230000007246 mechanism Effects 0.000 description 4
- 238000012545 processing Methods 0.000 description 4
- 230000004044 response Effects 0.000 description 4
- 230000007423 decrease Effects 0.000 description 3
- 238000012360 testing method Methods 0.000 description 3
- 238000004804 winding Methods 0.000 description 3
- 230000004075 alteration Effects 0.000 description 2
- 230000008901 benefit Effects 0.000 description 2
- 239000003990 capacitor Substances 0.000 description 2
- 230000006872 improvement Effects 0.000 description 2
- 230000008569 process Effects 0.000 description 2
- 230000001105 regulatory effect Effects 0.000 description 2
- 230000002411 adverse Effects 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 230000003750 conditioning effect Effects 0.000 description 1
- 238000013461 design Methods 0.000 description 1
- 238000001514 detection method Methods 0.000 description 1
- 230000005284 excitation Effects 0.000 description 1
- 230000006870 function Effects 0.000 description 1
- 238000009499 grossing Methods 0.000 description 1
- 230000010363 phase shift Effects 0.000 description 1
- 239000010453 quartz Substances 0.000 description 1
- 230000009467 reduction Effects 0.000 description 1
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N silicon dioxide Inorganic materials O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 1
- 230000003068 static effect Effects 0.000 description 1
- 238000012546 transfer Methods 0.000 description 1
Images
Classifications
-
- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06K—GRAPHICAL DATA READING; PRESENTATION OF DATA; RECORD CARRIERS; HANDLING RECORD CARRIERS
- G06K7/00—Methods or arrangements for sensing record carriers, e.g. for reading patterns
- G06K7/10—Methods or arrangements for sensing record carriers, e.g. for reading patterns by electromagnetic radiation, e.g. optical sensing; by corpuscular radiation
- G06K7/10009—Methods or arrangements for sensing record carriers, e.g. for reading patterns by electromagnetic radiation, e.g. optical sensing; by corpuscular radiation sensing by radiation using wavelengths larger than 0.1 mm, e.g. radio-waves or microwaves
- G06K7/10019—Methods or arrangements for sensing record carriers, e.g. for reading patterns by electromagnetic radiation, e.g. optical sensing; by corpuscular radiation sensing by radiation using wavelengths larger than 0.1 mm, e.g. radio-waves or microwaves resolving collision on the communication channels between simultaneously or concurrently interrogated record carriers.
-
- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06K—GRAPHICAL DATA READING; PRESENTATION OF DATA; RECORD CARRIERS; HANDLING RECORD CARRIERS
- G06K7/00—Methods or arrangements for sensing record carriers, e.g. for reading patterns
- G06K7/0008—General problems related to the reading of electronic memory record carriers, independent of its reading method, e.g. power transfer
-
- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06K—GRAPHICAL DATA READING; PRESENTATION OF DATA; RECORD CARRIERS; HANDLING RECORD CARRIERS
- G06K7/00—Methods or arrangements for sensing record carriers, e.g. for reading patterns
- G06K7/10—Methods or arrangements for sensing record carriers, e.g. for reading patterns by electromagnetic radiation, e.g. optical sensing; by corpuscular radiation
- G06K7/10009—Methods or arrangements for sensing record carriers, e.g. for reading patterns by electromagnetic radiation, e.g. optical sensing; by corpuscular radiation sensing by radiation using wavelengths larger than 0.1 mm, e.g. radio-waves or microwaves
- G06K7/10118—Methods or arrangements for sensing record carriers, e.g. for reading patterns by electromagnetic radiation, e.g. optical sensing; by corpuscular radiation sensing by radiation using wavelengths larger than 0.1 mm, e.g. radio-waves or microwaves the sensing being preceded by at least one preliminary step
- G06K7/10128—Methods or arrangements for sensing record carriers, e.g. for reading patterns by electromagnetic radiation, e.g. optical sensing; by corpuscular radiation sensing by radiation using wavelengths larger than 0.1 mm, e.g. radio-waves or microwaves the sensing being preceded by at least one preliminary step the step consisting of detection of the presence of one or more record carriers in the vicinity of the interrogation device
-
- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06K—GRAPHICAL DATA READING; PRESENTATION OF DATA; RECORD CARRIERS; HANDLING RECORD CARRIERS
- G06K19/00—Record carriers for use with machines and with at least a part designed to carry digital markings
- G06K19/06—Record carriers for use with machines and with at least a part designed to carry digital markings characterised by the kind of the digital marking, e.g. shape, nature, code
- G06K19/067—Record carriers with conductive marks, printed circuits or semiconductor circuit elements, e.g. credit or identity cards also with resonating or responding marks without active components
- G06K19/07—Record carriers with conductive marks, printed circuits or semiconductor circuit elements, e.g. credit or identity cards also with resonating or responding marks without active components with integrated circuit chips
- G06K19/0723—Record carriers with conductive marks, printed circuits or semiconductor circuit elements, e.g. credit or identity cards also with resonating or responding marks without active components with integrated circuit chips the record carrier comprising an arrangement for non-contact communication, e.g. wireless communication circuits on transponder cards, non-contact smart cards or RFIDs
-
- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06K—GRAPHICAL DATA READING; PRESENTATION OF DATA; RECORD CARRIERS; HANDLING RECORD CARRIERS
- G06K19/00—Record carriers for use with machines and with at least a part designed to carry digital markings
- G06K19/06—Record carriers for use with machines and with at least a part designed to carry digital markings characterised by the kind of the digital marking, e.g. shape, nature, code
- G06K19/067—Record carriers with conductive marks, printed circuits or semiconductor circuit elements, e.g. credit or identity cards also with resonating or responding marks without active components
- G06K19/07—Record carriers with conductive marks, printed circuits or semiconductor circuit elements, e.g. credit or identity cards also with resonating or responding marks without active components with integrated circuit chips
- G06K19/073—Special arrangements for circuits, e.g. for protecting identification code in memory
- G06K19/07309—Means for preventing undesired reading or writing from or onto record carriers
-
- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06K—GRAPHICAL DATA READING; PRESENTATION OF DATA; RECORD CARRIERS; HANDLING RECORD CARRIERS
- G06K19/00—Record carriers for use with machines and with at least a part designed to carry digital markings
- G06K19/06—Record carriers for use with machines and with at least a part designed to carry digital markings characterised by the kind of the digital marking, e.g. shape, nature, code
- G06K19/067—Record carriers with conductive marks, printed circuits or semiconductor circuit elements, e.g. credit or identity cards also with resonating or responding marks without active components
- G06K19/07—Record carriers with conductive marks, printed circuits or semiconductor circuit elements, e.g. credit or identity cards also with resonating or responding marks without active components with integrated circuit chips
- G06K19/073—Special arrangements for circuits, e.g. for protecting identification code in memory
- G06K19/07309—Means for preventing undesired reading or writing from or onto record carriers
- G06K19/07318—Means for preventing undesired reading or writing from or onto record carriers by hindering electromagnetic reading or writing
-
- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06K—GRAPHICAL DATA READING; PRESENTATION OF DATA; RECORD CARRIERS; HANDLING RECORD CARRIERS
- G06K7/00—Methods or arrangements for sensing record carriers, e.g. for reading patterns
- G06K7/10—Methods or arrangements for sensing record carriers, e.g. for reading patterns by electromagnetic radiation, e.g. optical sensing; by corpuscular radiation
- G06K7/10009—Methods or arrangements for sensing record carriers, e.g. for reading patterns by electromagnetic radiation, e.g. optical sensing; by corpuscular radiation sensing by radiation using wavelengths larger than 0.1 mm, e.g. radio-waves or microwaves
- G06K7/10237—Methods or arrangements for sensing record carriers, e.g. for reading patterns by electromagnetic radiation, e.g. optical sensing; by corpuscular radiation sensing by radiation using wavelengths larger than 0.1 mm, e.g. radio-waves or microwaves the reader and the record carrier being capable of selectively switching between reader and record carrier appearance, e.g. in near field communication [NFC] devices where the NFC device may function as an RFID reader or as an RFID tag
-
- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06K—GRAPHICAL DATA READING; PRESENTATION OF DATA; RECORD CARRIERS; HANDLING RECORD CARRIERS
- G06K7/00—Methods or arrangements for sensing record carriers, e.g. for reading patterns
- G06K7/10—Methods or arrangements for sensing record carriers, e.g. for reading patterns by electromagnetic radiation, e.g. optical sensing; by corpuscular radiation
- G06K7/10009—Methods or arrangements for sensing record carriers, e.g. for reading patterns by electromagnetic radiation, e.g. optical sensing; by corpuscular radiation sensing by radiation using wavelengths larger than 0.1 mm, e.g. radio-waves or microwaves
- G06K7/10366—Methods or arrangements for sensing record carriers, e.g. for reading patterns by electromagnetic radiation, e.g. optical sensing; by corpuscular radiation sensing by radiation using wavelengths larger than 0.1 mm, e.g. radio-waves or microwaves the interrogation device being adapted for miscellaneous applications
- G06K7/10376—Methods or arrangements for sensing record carriers, e.g. for reading patterns by electromagnetic radiation, e.g. optical sensing; by corpuscular radiation sensing by radiation using wavelengths larger than 0.1 mm, e.g. radio-waves or microwaves the interrogation device being adapted for miscellaneous applications the interrogation device being adapted for being moveable
- G06K7/10386—Methods or arrangements for sensing record carriers, e.g. for reading patterns by electromagnetic radiation, e.g. optical sensing; by corpuscular radiation sensing by radiation using wavelengths larger than 0.1 mm, e.g. radio-waves or microwaves the interrogation device being adapted for miscellaneous applications the interrogation device being adapted for being moveable the interrogation device being of the portable or hand-handheld type, e.g. incorporated in ubiquitous hand-held devices such as PDA or mobile phone, or in the form of a portable dedicated RFID reader
-
- H04B5/45—
Definitions
- Embodiments generally relate to systems using transponders, that is, transceivers (generally mobile) capable of communicating in a contactless and wireless manner with a terminal. Embodiments more specifically relate to the securing of a near field communication between a transponder and a reader.
- Electromagnetic transponder systems are more and more used with the coming up of mobile telecommunication devices equipped with near field communication routers (NFC).
- the mobile equipment may be used both as a transponder reader, for example, as a contactless chip card reader and, conversely, as an actual transponder for a near field communication with a terminal, for example, another mobile device, an access terminal, etc.
- GB-A-2464362 discloses a communication interface comprising a RFID reader glove.
- EP-A-2077518 discloses a detection system of the presence of a transponder by reduction of the resonance frequency.
- An embodiment provides a mechanism for protecting a communication between an electromagnetic transponder and a terminal, which overcomes all or part of the disadvantages of usual solutions.
- Another embodiment provides a solution which does not require establishing a communication to detect the possible presence of a pirate transponder.
- one provides a method for protecting a communication between an electromagnetic transponder and a terminal, wherein the transmission of a polling request by the terminal is only allowed when the transponder is in mechanical contact or in quasi-mechanical contact with the terminal.
- the sending of the request is preceded by an increase in the value of a resistive element of the oscillating circuit if the second value is greater than 2.
- the possible transmission of a request is blocked.
- step b) is preceded by a comparison of the first value with the no-load value
- step c it is proceeded to step c).
- One also provides a terminal of communication with an electromagnetic transponder, comprising means capable of implementing the method.
- FIG. 1 very schematically shows an example of a transponder near-field communication system
- FIG. 2 is a simplified block diagram of the terminal of FIG. 1 ;
- FIG. 3 is a simplified block diagram of the transponder of FIG. 1 ;
- FIG. 4 illustrates an example of the variation of the voltage across the resonant circuit of the transponder according to a normalized coupling
- FIG. 5 illustrates the variation of a current ratio in the oscillating circuit of the reader according to the coupling
- FIG. 6 is a simplified flowchart illustrating an implementation mode of the protection method
- FIG. 7 is a block diagram illustrating an alternative embodiment of a terminal.
- FIG. 8 is a partial block diagram illustrating an initialization of a communication by a terminal.
- FIG. 1 very schematically shows an example of a communication and remote-supply system comprising a terminal 1 or read and/or write terminal, and a transponder 2 .
- terminal 1 for example, a cell phone or smartphone
- terminal 1 comprises a series oscillating circuit, formed of an inductance L 1 in series with a capacitor C 1 and a resistor R 1 .
- This series oscillating circuit is controlled by a device 11 comprising, among others and without this being a limitation, an amplifier or antenna coupler and a transmission control and exploitation circuit especially comprising a modulator/demodulator and a command and data processing circuit (generally, a microprocessor).
- Device 11 generally communicates with different input/output circuits (keyboard, display, element of exchange with a server, etc.) and/or processing circuits, not shown.
- the elements of terminal 1 most often draw the power necessary to their operation from a supply circuit (not shown) connected, for example, to the power line distribution system (mains) or to a battery (for example, that of an automobile vehicle or of a portable telephone or computer).
- a transponder 2 capable of cooperating with terminal 1 comprises an oscillating circuit, for example, parallel, formed of an inductance L 2 in parallel with a capacitor C 2 between two input terminals 22 and 23 of a control and processing circuit 21 .
- Terminals 22 and 23 are, in practice, connected to input terminals of a rectifying element (not shown in FIG. 1 ) having output terminals forming terminals for supplying the circuits internal to the transponder.
- Such circuits generally comprise a memory and a modulator for transmitting data to the terminal.
- these circuits may also comprise a demodulator of the signals that may be received from the terminal, a microprocessor, and various other processing circuits.
- the oscillating circuits of the terminal and of the transponder are generally tuned to a same frequency corresponding to the frequency of an excitation signal of the oscillating circuit of the terminal.
- This high-frequency signal (for example, at 13.56 MHz) is used not only as a data transmission carrier from the terminal to the transponder, but also as a remote-supply carrier for the transponders located in the field of the terminal.
- a transponder 2 is in the field of terminal 1 , a high-frequency voltage is generated between terminals 21 and 23 of the resonant circuit of the transponder. This voltage is used to provide the power supply voltage of electronic circuits 21 of the transponder.
- FIG. 2 is a block diagram of an embodiment of a terminal 1 .
- the terminal comprises an oscillating circuit formed of an inductance or antenna L 1 in series with a capacitive element C 1 and with a resistive element R 1 .
- the resistive element is an element of settable value (CONTROLLABLE R 1 ).
- these elements are connected between an output terminal 12 of an amplifier or antenna coupler 14 and a terminal 13 at a reference voltage (generally the ground).
- An element 15 for measuring the current in the oscillating circuit is interposed, for example, between capacitive element C and ground 13 .
- Measurement element 15 belongs to a phase regulation loop which will be described hereafter.
- Amplifier 14 receives a high-frequency transmission signal E originating from a modulator 16 (MOD) which receives a reference frequency (signal OSC), for example, from a quartz oscillator (not shown).
- Modulator 16 receives, if need be, a data signal Tx to be transmitted and, in the absence of any data transmission from the terminal, provides the high-frequency carrier (for example, at 13.56 MHz) capable of remotely supplying a transponder.
- Capacitive element C 1 preferably is a variable-capacitance element controllable by a signal CTRL. The phase of the current in antenna L 1 is regulated with respect to a reference signal.
- This regulation is a regulation of the high-frequency signal, that is, of the carrier signal corresponding to signal E in the absence of data to be transmitted.
- the regulation is performed by varying capacitance C 1 of the oscillating circuit of the terminal to maintain the current in antenna L 1 in constant phase relationship with the reference signal.
- the reference signal for example corresponds to signal OSC provided by the oscillator to the modulator.
- Signal CTRL originates from a circuit 17 (COMP) having the function of detecting the phase shift with respect to the reference signal and to accordingly modify the capacitance of element C 1 .
- the phase measurement is, for example, performed from a measurement of current I in the oscillating circuit by means of measurement element 15 .
- this element is formed of a current transformer comprising a primary winding 151 between element C 1 and ground terminal 13 , and a secondary winding 152 having a first terminal directly connected to ground and having its other terminal providing a signal MES indicative of the result of the measurement.
- a current-to-voltage conversion resistor 153 is connected in parallel with secondary winding 152 .
- the result of measurement MES is sent to comparator 17 , which accordingly controls the value of capacitive element C 1 by means of signal CTRL.
- comparator 17 uses the same phase demodulator (not shown) as that which is used to demodulate the signal originating from the transponder and which is possibly received by the oscillating circuit. Accordingly, comparator 17 provides a signal Rx giving back a possible retromodulation of the data received from a transponder to a block 18 symbolizing the rest of the electronic circuits of the terminal.
- the response time of the phase regulation loop is selected to be sufficiently long to avoid disturbing the possible retromodulation from a transponder and sufficiently short as compared with the speed at which a transponder passes in the field of the terminal.
- One can speak of a static regulation with respect to the modulation frequencies for example, a 13.56-MHz frequency of the remote supply carrier and a 847.5-kHz retromodulation frequency used to transmit data from the transponder to the terminal).
- other current measurement elements may be used (for example, a resistor).
- phase regulation terminal An example of a phase regulation terminal is described in document EP-A-0857981.
- FIG. 3 shows an embodiment of a transponder 2 .
- a rectifying element 25 for example, a fullwave rectifying bridge.
- the rectified outputs of bridge 25 are interconnected by a smoothing capacitive element C 25 and provide a voltage V 25 to a circuit 26 (ALIM) for managing the transponder power supply.
- Circuit 26 supplies the other transponder circuits, symbolized by a block 27 , with the power necessary to their operation.
- Elements 25 , C 25 , 26 , and 27 are, in FIG. 1 , comprised in block 21 .
- Circuit 27 samples data between terminals 22 and 23 of the resonant circuit to be able to demodulate the possible data received from the terminal before rectification. Further, circuit 27 comprises so-called retromodulation capacitive and/or resistive elements, not shown, capable of modulating the load (LOAD) formed by the transponder on the field generated by the terminal.
- This load modification translates, on the terminal side, as a modification of the current or of the voltage of its oscillating circuit (assuming that amplifier or antenna coupler 14 , in FIG. 2 , is capable of providing a constant current).
- This current or voltage modification detected by the intensity transformer ( 15 , FIG. 2 ) or by any other measurement element (for example, the voltage measurement across capacitive element C 1 ), enables the terminal to decode the data received from the transponder.
- phase is regulated on the terminal side enables using current and voltage measurements in the oscillating circuit of the terminal to deduce information relative to the transponder coupling when it is in the field of the terminal.
- Such information takes into account, in particular, the coupling between the transponder and the terminal, that is, the coefficient of the coupling between the oscillating circuit of the terminal and that of the transponder.
- This coupling coefficient essentially depends on the distance separating the transponder from the terminal.
- the position where the transponder is placed against the terminal is considered as the maximum coupling position. Indeed, the antennas of the transponder and of the terminal cannot be brought closer to each other, unless the terminal package is eliminated.
- FIG. 4 shows an example of the shape of voltage V C2 recovered on the transponder side according to normalized coupling k/k opt .
- the curve starts from the origin of ordinates (zero voltage) for a zero coupling. This corresponds to a distance from the transponder to the terminal such that no signal can be sensed by the transponder.
- the maximum coupling position is at a given location of this curve, but not necessarily at the optimum coupling position. This, in particular, depends on the different values of the capacitive and resistive elements.
- the aim is to avoid for a pirate device, generally more bulky or of different nature than the transponder for which the terminal is intended to establish a communication with the terminal while being far away from it.
- Another aim is to reassure the bearer of the transponder. Indeed, applications often concern payments or authentications. The fact to only enable a communication to be established when the transponder is “laid” on the terminal reassures the user.
- the transponder is provided to force the user to place the transponder in a quasi-contact position (distance shorter than 1 mm), preferably in mechanical contact, with the terminal package, be it by moving the terminal or the transponder according to cases.
- This package comprises the communication antenna. This therefore amounts to forcing the transponder to be in a position of maximum coupling with its terminal. To achieve this, the transmission of a request to a transponder is only allowed from the moment that the terminal detects this maximum coupling position.
- the notion of contact used herein relates to a mechanical contact with the terminal package, that is, a position where the antennas of the terminal and of the transponder are as close as possible to each other. It is not an electric contact, the communication and the possible remote supply of the transponder always being performed with no electric contact.
- the position corresponding to a zero coupling corresponds to a position of the terminal with no transponder.
- Current I FIG. 2
- I NO-LOAD This no-load value corresponds to the value while no transponder is in the field of the terminal.
- FIG. 5 illustrates the variation of ratio I V /I according to coupling k.
- V C2max is reached for a value of current coupling k which is either lower or greater than the optimum coupling.
- measuring current I and knowing no-load current I V is sufficient to determine current coupling k with respect to optimum coupling k opt .
- FIG. 6 is a simplified flowchart of an implementation mode of the transaction protection method.
- the terminal periodically measures (block 41 , MES I i ) the current value of current I in its oscillating circuit.
- the measurement periodicity is selected to be as short as possible while remaining compatible with the time necessary to exploit the measurements (to execute the method between two measurements).
- Such a storage is, for example, performed in a terminal initialization phase.
- the current value is equal to the no-load value (output Y of block 42 ), this means that no transponder is present in the field and it is proceeded to a next iteration of the measurements (block 43 , NEXT i ). If the current value is different from the no-load value (output N of block 42 ), this means that there is an element in front of the terminal. It is, however, not known for the time being whether it is an authorized transponder or a pirate device, and the distance between the transponder and the terminal remains to be determined.
- a terminal periodically and permanently sends polling requests to possible transponders present in its field.
- this sending of requests is restricted to only be performed once it is known that a transponder which appears to be authorized is in the field.
- Limiting value I lim corresponds to a known value for a given terminal capable of operating with a family of transponders for which it is provided.
- the value of limiting current I lim is determined, for example, on design of the terminal or in an initial configuration phase. The aim is to determine and to store the current at the maximum coupling with an authorized transponder type. Several limiting current values may be stored to authorize several transponder types.
- the transponder may thus be a pirate device and it is proceeded to the input of block 45 forbidding the sending of a request.
- output N of block 46 it is considered that an authorized transponder is laid against the reader and that it is not a pirate device.
- the sending of a request by the terminal is then authorized (block 47 , SEND REQ).
- Allowing/forbidding the sending of one or several requests amounts, in a simple embodiment, to modifying the state of a bit (flag) conditioning the sending of requests REQ.
- step 45 may be omitted, which means there then is no proper forbidding procedure.
- the terminal simply only enters a polling process (sending of requests) if an authorized transponder, in contact, is detected.
- the relations between the coupling and the current in the oscillating circuit of the terminal are exploited to have the maximum coupling coincide with the optimum coupling, if possible, and thus optimize the security of the communication. Indeed, this imposes an operating point such that, as soon as the transponder moves away, this reflects as a decrease in the recovered voltage.
- FIG. 7 is a block diagram to be compared with that of FIG. 2 partially illustrating an embodiment of a circuit 30 (controllable R 1 ) for varying the value of resistance R 1 .
- a variable resistor 31 is connected in series with a fixed resistor 32 , the two resistors 31 and 32 forming the current resistive element of the terminal.
- comparator 37 is used to control the value of resistive element 31 with the reference value by means of a control circuit 38 (CT).
- CT control circuit 38
- the other terminal elements are identical to those described in relation with FIG. 2 .
- circuit 30 is placed on the side of ground terminal 13 rather than on the side of output terminal 12 of amplifier 14 (not shown in FIG. 7 ).
- Current transformer 15 used for the measurement and the phase control is interposed between capacitive element C 1 and circuit 30 .
- Capacitance C 1 is preferably also variable, although this has not been illustrated in FIG. 7 .
- FIG. 8 illustrates a mechanism for sending requests REQ from a terminal to a transponder.
- This mechanism which is usual per se, is usually permanently implemented in a terminal but is, according to the described embodiments, only implemented at block 47 .
- the transponder read-write terminal starts (block 60 , ST) after a turn-on, initialization, and test phase, a standby procedure during which it waits for a communication to be established with at least one transponder.
- This procedure essentially comprises periodically sending (block 47 ) a polling sequence (REQ) to transponders that may be present in the field of the terminal.
- REQ polling sequence
- this request sending 47 is only performed once the fact that the transponder is in contact with the terminal has been validated.
- the reader monitors (block 62 , ATQ?) the reception by its demodulator of a response message ATQ from a transponder which would have entered its field.
- the reader In the absence of a response, the reader loops onto the sending of a polling 47 .
- the reader When it receives a response ATQ, it passes to a mode where it is checked that the transponder actually is a transponder intended for it as well as to a possible anti-collision mode (block 63 ) to individualize the transponders in its field.
Abstract
A method for protecting communication between an electromagnetic transponder and a terminal, wherein the transmission of a polling request by the terminal is only allowed when the transponder is in mechanical contact or in quasi-mechanical contact with the terminal.
Description
- This application is the U.S. National Stage of international patent application number PCT/FR2012/050842, filed on Apr. 18, 2012, which claims the priority benefit of French patent application number 11/54863, filed on Jun. 3, 2011, which applications are hereby incorporated by reference to the maximum extent allowable by law.
- 1. Technical Field
- Embodiments generally relate to systems using transponders, that is, transceivers (generally mobile) capable of communicating in a contactless and wireless manner with a terminal. Embodiments more specifically relate to the securing of a near field communication between a transponder and a reader.
- 2. Discussion of the Related Art
- Electromagnetic transponder systems are more and more used with the coming up of mobile telecommunication devices equipped with near field communication routers (NFC). In such devices, the mobile equipment may be used both as a transponder reader, for example, as a contactless chip card reader and, conversely, as an actual transponder for a near field communication with a terminal, for example, another mobile device, an access terminal, etc.
- Many methods aiming at protecting transactions between an electromagnetic transponder and a reader are known. Such mechanisms generally use systems for encrypting communications, be it by symmetrical or asymmetrical algorithms.
- All these systems require an established communication to make a protection of the transaction possible.
- Further, such methods are generally inefficient to prevent a pirate device simulating a transponder from starting a communication with a reader.
- GB-A-2464362 discloses a communication interface comprising a RFID reader glove.
- EP-A-2077518 discloses a detection system of the presence of a transponder by reduction of the resonance frequency.
- An embodiment provides a mechanism for protecting a communication between an electromagnetic transponder and a terminal, which overcomes all or part of the disadvantages of usual solutions.
- Another embodiment provides a solution which does not require establishing a communication to detect the possible presence of a pirate transponder.
- Another embodiment provides a solution compatible with usual communication encryption processes.
- To achieve all or part of these and other objects, one provides a method for protecting a communication between an electromagnetic transponder and a terminal, wherein the transmission of a polling request by the terminal is only allowed when the transponder is in mechanical contact or in quasi-mechanical contact with the terminal.
- According to an embodiment:
-
- a) a first value of the current in an oscillating circuit of the terminal is periodically measured;
- b) a second value of a ratio between a no-load value of this current, stored when no transponder is in the field of the terminal, and the first value, is calculated;
- c) said second value is compared with a third value of said ratio calculated in a previous iteration; and
- d) as long as the second and third values are not equal, steps a to c are repeated.
- According to an embodiment, in case the second and third values are equal:
-
- e) the second value is compared with a threshold;
- f) the sending of a request is allowed if this threshold has not been reached;
- g) it is returned to step a) if this threshold has been exceeded.
- According to an embodiment, if said threshold has been reached, the sending of the request is preceded by an increase in the value of a resistive element of the oscillating circuit if the second value is greater than 2.
- According to an embodiment, if the second value is smaller than the third one, the possible transmission of a request is blocked.
- According to an embodiment:
- step b) is preceded by a comparison of the first value with the no-load value; and
- in case of an identity, it is returned to step a), or
- in the opposite case, it is proceeded to step c).
- One also provides a terminal of communication with an electromagnetic transponder, comprising means capable of implementing the method.
- One also provides a cell phone comprising such a terminal.
- The foregoing and other objects, features, and advantages will be discussed in detail in the following non-limiting description of specific embodiments in connection with the accompanying drawings, among which:
- .among which:
-
FIG. 1 very schematically shows an example of a transponder near-field communication system; -
FIG. 2 is a simplified block diagram of the terminal ofFIG. 1 ; -
FIG. 3 is a simplified block diagram of the transponder ofFIG. 1 ; -
FIG. 4 illustrates an example of the variation of the voltage across the resonant circuit of the transponder according to a normalized coupling; -
FIG. 5 illustrates the variation of a current ratio in the oscillating circuit of the reader according to the coupling; -
FIG. 6 is a simplified flowchart illustrating an implementation mode of the protection method; -
FIG. 7 is a block diagram illustrating an alternative embodiment of a terminal; and -
FIG. 8 is a partial block diagram illustrating an initialization of a communication by a terminal. - The same elements have been designated with the same reference numerals in the different drawings. For clarity, only those steps and elements which are useful to the understanding of the described embodiments have been shown and will be detailed. In particular, the origin and the destination of the data transmitted in communications between a transponder and a terminal have not been detailed, the described embodiments being compatible with any usual communication.
-
FIG. 1 very schematically shows an example of a communication and remote-supply system comprising aterminal 1 or read and/or write terminal, and atransponder 2. - Generally, terminal 1 (for example, a cell phone or smartphone) comprises a series oscillating circuit, formed of an inductance L1 in series with a capacitor C1 and a resistor R1. This series oscillating circuit is controlled by a device 11 comprising, among others and without this being a limitation, an amplifier or antenna coupler and a transmission control and exploitation circuit especially comprising a modulator/demodulator and a command and data processing circuit (generally, a microprocessor). Device 11 generally communicates with different input/output circuits (keyboard, display, element of exchange with a server, etc.) and/or processing circuits, not shown. The elements of
terminal 1 most often draw the power necessary to their operation from a supply circuit (not shown) connected, for example, to the power line distribution system (mains) or to a battery (for example, that of an automobile vehicle or of a portable telephone or computer). - A
transponder 2 capable of cooperating withterminal 1 comprises an oscillating circuit, for example, parallel, formed of an inductance L2 in parallel with a capacitor C2 between twoinput terminals processing circuit 21.Terminals FIG. 1 ) having output terminals forming terminals for supplying the circuits internal to the transponder. Such circuits generally comprise a memory and a modulator for transmitting data to the terminal. According to the transponder type (depending on the application and on the tasks that it is supposed to perform), these circuits may also comprise a demodulator of the signals that may be received from the terminal, a microprocessor, and various other processing circuits. - The oscillating circuits of the terminal and of the transponder are generally tuned to a same frequency corresponding to the frequency of an excitation signal of the oscillating circuit of the terminal. This high-frequency signal (for example, at 13.56 MHz) is used not only as a data transmission carrier from the terminal to the transponder, but also as a remote-supply carrier for the transponders located in the field of the terminal. When a
transponder 2 is in the field ofterminal 1, a high-frequency voltage is generated betweenterminals electronic circuits 21 of the transponder. -
FIG. 2 is a block diagram of an embodiment of aterminal 1. As indicated previously, the terminal comprises an oscillating circuit formed of an inductance or antenna L1 in series with a capacitive element C1 and with a resistive element R1. The resistive element is an element of settable value (CONTROLLABLE R1). In the example ofFIG. 2 , these elements are connected between anoutput terminal 12 of an amplifier orantenna coupler 14 and a terminal 13 at a reference voltage (generally the ground). Anelement 15 for measuring the current in the oscillating circuit is interposed, for example, between capacitive element C andground 13.Measurement element 15 belongs to a phase regulation loop which will be described hereafter.Amplifier 14 receives a high-frequency transmission signal E originating from a modulator 16 (MOD) which receives a reference frequency (signal OSC), for example, from a quartz oscillator (not shown).Modulator 16 receives, if need be, a data signal Tx to be transmitted and, in the absence of any data transmission from the terminal, provides the high-frequency carrier (for example, at 13.56 MHz) capable of remotely supplying a transponder. Capacitive element C1 preferably is a variable-capacitance element controllable by a signal CTRL. The phase of the current in antenna L1 is regulated with respect to a reference signal. This regulation is a regulation of the high-frequency signal, that is, of the carrier signal corresponding to signal E in the absence of data to be transmitted. The regulation is performed by varying capacitance C1 of the oscillating circuit of the terminal to maintain the current in antenna L1 in constant phase relationship with the reference signal. The reference signal for example corresponds to signal OSC provided by the oscillator to the modulator. Signal CTRL originates from a circuit 17 (COMP) having the function of detecting the phase shift with respect to the reference signal and to accordingly modify the capacitance of element C1. The phase measurement is, for example, performed from a measurement of current I in the oscillating circuit by means ofmeasurement element 15. In the shown example, this element is formed of a current transformer comprising a primary winding 151 between element C1 andground terminal 13, and a secondary winding 152 having a first terminal directly connected to ground and having its other terminal providing a signal MES indicative of the result of the measurement. A current-to-voltage conversion resistor 153 is connected in parallel with secondary winding 152. The result of measurement MES is sent tocomparator 17, which accordingly controls the value of capacitive element C1 by means of signal CTRL. - In the embodiment illustrated in
FIG. 2 ,comparator 17 uses the same phase demodulator (not shown) as that which is used to demodulate the signal originating from the transponder and which is possibly received by the oscillating circuit. Accordingly,comparator 17 provides a signal Rx giving back a possible retromodulation of the data received from a transponder to ablock 18 symbolizing the rest of the electronic circuits of the terminal. - The response time of the phase regulation loop is selected to be sufficiently long to avoid disturbing the possible retromodulation from a transponder and sufficiently short as compared with the speed at which a transponder passes in the field of the terminal. One can speak of a static regulation with respect to the modulation frequencies (for example, a 13.56-MHz frequency of the remote supply carrier and a 847.5-kHz retromodulation frequency used to transmit data from the transponder to the terminal).
- As a variation of the intensity transformer of
FIG. 2 , other current measurement elements may be used (for example, a resistor). - An example of a phase regulation terminal is described in document EP-A-0857981.
-
FIG. 3 shows an embodiment of atransponder 2. Betweenterminals element 25, for example, a fullwave rectifying bridge. The rectified outputs ofbridge 25 are interconnected by a smoothing capacitive element C25 and provide a voltage V25 to a circuit 26 (ALIM) for managing the transponder power supply.Circuit 26 supplies the other transponder circuits, symbolized by ablock 27, with the power necessary to their operation.Elements 25, C25, 26, and 27 are, inFIG. 1 , comprised inblock 21.Circuit 27 samples data betweenterminals circuit 27 comprises so-called retromodulation capacitive and/or resistive elements, not shown, capable of modulating the load (LOAD) formed by the transponder on the field generated by the terminal. This load modification translates, on the terminal side, as a modification of the current or of the voltage of its oscillating circuit (assuming that amplifier orantenna coupler 14, inFIG. 2 , is capable of providing a constant current). This current or voltage modification, detected by the intensity transformer (15,FIG. 2 ) or by any other measurement element (for example, the voltage measurement across capacitive element C1), enables the terminal to decode the data received from the transponder. - The fact that the phase is regulated on the terminal side enables using current and voltage measurements in the oscillating circuit of the terminal to deduce information relative to the transponder coupling when it is in the field of the terminal.
- Such information takes into account, in particular, the coupling between the transponder and the terminal, that is, the coefficient of the coupling between the oscillating circuit of the terminal and that of the transponder. This coupling coefficient essentially depends on the distance separating the transponder from the terminal. The coupling coefficient, designated as k, between the oscillating circuits of a transponder and of a terminal, always ranges between 0 and 1.
- The position where the transponder is placed against the terminal is considered as the maximum coupling position. Indeed, the antennas of the transponder and of the terminal cannot be brought closer to each other, unless the terminal package is eliminated.
- It is further now known that an optimum coupling position kopt, corresponding to the position at which voltage VC2 recovered across the transponder (more specifically across its antenna) is maximum, exists between the terminal and the transponder. This optimum coupling position does not necessarily correspond to the maximum coupling position.
-
FIG. 4 shows an example of the shape of voltage VC2 recovered on the transponder side according to normalized coupling k/kopt. - The curve starts from the origin of ordinates (zero voltage) for a zero coupling. This corresponds to a distance from the transponder to the terminal such that no signal can be sensed by the transponder. Voltage VC2 reaches a maximum VC2opt for an optimum coupling coefficient kopt k/k
opt =1), then decreases to an intermediate value VC2(1) reached atcoupling 1. The maximum coupling position is at a given location of this curve, but not necessarily at the optimum coupling position. This, in particular, depends on the different values of the capacitive and resistive elements. - Other remarkable points of the curve of
FIG. 4 are points of inflexion where ratio k/kopt is respectively equal to 1/{square root over (√3)} and to {square root over (√3)}, and where voltage VC2 has the same value on the transponder side. - Relations expressing voltage value VC2 according to the ratio of the current coupling to the optimum coupling and linking these values to current I in the oscillating circuit of the terminal have become usual. For example, such relations are provided in document EP-A-2114019 (B8723-07-RO-225).
- According to the described embodiments, it is provided to exploit these relations to force the bearer of the transponder to come as close as possible to the terminal. The aim then is to avoid for a pirate device, generally more bulky or of different nature than the transponder for which the terminal is intended to establish a communication with the terminal while being far away from it.
- Another aim is to reassure the bearer of the transponder. Indeed, applications often concern payments or authentications. The fact to only enable a communication to be established when the transponder is “laid” on the terminal reassures the user.
- For this purpose, it is provided to force the user to place the transponder in a quasi-contact position (distance shorter than 1 mm), preferably in mechanical contact, with the terminal package, be it by moving the terminal or the transponder according to cases. This package comprises the communication antenna. This therefore amounts to forcing the transponder to be in a position of maximum coupling with its terminal. To achieve this, the transmission of a request to a transponder is only allowed from the moment that the terminal detects this maximum coupling position. The notion of contact used herein relates to a mechanical contact with the terminal package, that is, a position where the antennas of the terminal and of the transponder are as close as possible to each other. It is not an electric contact, the communication and the possible remote supply of the transponder always being performed with no electric contact.
- The position corresponding to a zero coupling (
FIG. 4 ) corresponds to a position of the terminal with no transponder. Current I (FIG. 2 ) in the antenna or the oscillating circuit of the terminal has a so-called no-load value, noted IV or INO-LOAD. This no-load value corresponds to the value while no transponder is in the field of the terminal. - As indicated, for example, in above-mentioned document EP-A-2114019, the ratio of current coupling k to optimum coupling kopt is linked to the no-load current and to the current value, noted I, of current I by the following relation:
-
(k/k opt) 2 =I V /I − 1. - This relation may also be written as:
-
I V /I=(k/k opt) 2+1. - In the optimum coupling position (k=kopt), the current is Iopt=IV/2. Further, there appears from the above formula that, in optimum coupling position, ratio IV/I=2.
-
FIG. 5 illustrates the variation of ratio IV/I according to coupling k. - This curve is remarkable in that it is linear from the zero coupling (IV/I=1) through the point where the optimum coupling provides a ratio IV/I=2. Two other remarkable points appear on the curve of
FIG. 5 . These points are the points of inflexion in the curve ofFIG. 4 . In the positions corresponding to these points of inflexion, this translates, on the terminal side, as a current ratio IV/I respectively equal to 1.33 (k=kopt/{square root over (√3)} and 4 (k={square root over (√3)}·kopt). - It is also known that value VC2max is reached for a value of current coupling k which is either lower or greater than the optimum coupling.
- Thus, measuring current I and knowing no-load current IV is sufficient to determine current coupling k with respect to optimum coupling kopt.
- It should be noted that when it is spoken of measuring current I, the obtaining of data representative of current I is considered. However, a measurement of the current is preferred to a measurement of the voltage, which is more difficult to compare.
-
FIG. 6 is a simplified flowchart of an implementation mode of the transaction protection method. - The terminal periodically measures (block 41, MES Ii) the current value of current I in its oscillating circuit. The measurement periodicity is selected to be as short as possible while remaining compatible with the time necessary to exploit the measurements (to execute the method between two measurements). After each measurement, the current value is compared with the no-load value stored while no transponder is present in the field of the terminal (block 42, Ii=Iv?). Such a storage is, for example, performed in a terminal initialization phase.
- If the current value is equal to the no-load value (output Y of block 42), this means that no transponder is present in the field and it is proceeded to a next iteration of the measurements (block 43, NEXTi). If the current value is different from the no-load value (output N of block 42), this means that there is an element in front of the terminal. It is, however, not known for the time being whether it is an authorized transponder or a pirate device, and the distance between the transponder and the terminal remains to be determined.
- The ratio between the no-load value of current Iv and current value Ii is then calculated and this ratio is compared with ratio (Iv/Ii−1) calculated at the previous iteration (block 44, Iv/Ii=Iv/Ii−1?) and stored. This test amounts to determining whether the distance between the transponder and the terminal varies.
- If the distance varies (output N of block 44), that is, the user moves one of the two elements with respect to the other, the transponder cannot be in contact with the terminal. The sending of a polling request by the terminal to the transponder is then forbidden (block 45, DO NOT SEND REQ) and it is looped onto a next measurement (block 43).
- Usually, a terminal periodically and permanently sends polling requests to possible transponders present in its field. Here, this sending of requests is restricted to only be performed once it is known that a transponder which appears to be authorized is in the field.
- If the distance no longer varies (output Y of block 44), the current ratio is then compared (block 46, Iv/Ii>IV/Ilim?) with a ratio with a limiting current IV/Ilim. Limiting value Ilim corresponds to a known value for a given terminal capable of operating with a family of transponders for which it is provided. The value of limiting current Ilim is determined, for example, on design of the terminal or in an initial configuration phase. The aim is to determine and to store the current at the maximum coupling with an authorized transponder type. Several limiting current values may be stored to authorize several transponder types.
- If the current ratio is greater than the ratio with the limiting current (output Y of block 46), this means that the current coupling is greater than the maximum coupling. The transponder may thus be a pirate device and it is proceeded to the input of
block 45 forbidding the sending of a request. - In the opposite case (output N of block 46) and according to a simplified embodiment, it is considered that an authorized transponder is laid against the reader and that it is not a pirate device. The sending of a request by the terminal is then authorized (block 47, SEND REQ).
- According to a first optional variation illustrated in dotted lines, as long as the transponder is not stopped against the terminal package (output N of block 44), it is checked whether the current ratio is greater than the previous ratio (block 48, Iv/Ii>Iv/Ii−1?). If it is (output Y of block 48), this means that the card is approaching and it is proceeded to step 43. If it is not (output N of block 48), this means that the card is moving away and before proceeding to the next iteration, the sending of requests is forbidden (block 45).
- Allowing/forbidding the sending of one or several requests amounts, in a simple embodiment, to modifying the state of a bit (flag) conditioning the sending of requests REQ. As a variation, step 45 may be omitted, which means there then is no proper forbidding procedure. The terminal simply only enters a polling process (sending of requests) if an authorized transponder, in contact, is detected.
- According to another optional variation, the relations between the coupling and the current in the oscillating circuit of the terminal are exploited to have the maximum coupling coincide with the optimum coupling, if possible, and thus optimize the security of the communication. Indeed, this imposes an operating point such that, as soon as the transponder moves away, this reflects as a decrease in the recovered voltage.
- According to this variation illustrated in dotted lines in
FIG. 6 , once tests 44 and 46 have validated the fact that the maximum coupling position has been reached, a comparison (block 49, IV/I<2?) of the current value of ratio (IV/I) with 2, that is, with the optimum coupling position, is performed. If the current position is lower than the optimum coupling position (output Y of block 49), this means that the optimum coupling cannot be reached. Indeed, resistance R1 preferentially is, at the initialization, at its minimum value, and its value can no longer be increased without adversely affecting other functional aspects of the system. The request is then sent (block 47, SEND REQ). - In the opposite case (output N of block 49), a variation (block 50, INCREASE R1 AND REACH IV/I<=2) of resistance R1 of the oscillating circuit of the terminal is caused until the maximum coupling is smaller than or equal to the optimum coupling. Such an optional setting is known per se (see the above-mentioned document). This then enables to make sure that the transponder remote supply can only decrease monotonically and decreasingly if the transponder moves away. The communication will then be rapidly cut if the transponder moves away and the interposition of a pirate device between the terminal and the transponder is thus avoided, even once the communication has been initiated. The limit is however selected to maintain the possibility of a sufficient contactless power transfer for the transponder circuits to be properly supplied.
-
FIG. 7 is a block diagram to be compared with that ofFIG. 2 partially illustrating an embodiment of a circuit 30 (controllable R1) for varying the value of resistance R1. In this example, avariable resistor 31 is connected in series with a fixedresistor 32, the tworesistors -
Current transformer 15 measures current Ii and delivers a measurement tocircuit 36, which calculates ratio Iv/Ii. The value of this ratio is then compared by a comparison circuit 37 (COMP) with a reference value (Iv/I)cons that may be smaller than or equal to 2 according to the second variation ofFIG. 6 . - The result provided by
comparator 37 is used to control the value ofresistive element 31 with the reference value by means of a control circuit 38 (CT). The other terminal elements are identical to those described in relation withFIG. 2 . However, in the example ofFIG. 7 ,circuit 30 is placed on the side ofground terminal 13 rather than on the side ofoutput terminal 12 of amplifier 14 (not shown inFIG. 7 ).Current transformer 15 used for the measurement and the phase control is interposed between capacitive element C1 andcircuit 30. Capacitance C1 is preferably also variable, although this has not been illustrated inFIG. 7 . - An example of a switchable resistor circuit that may be used to implement the resistive selection of the value of resistance R1 is, for example, described in the above-mentioned document.
-
FIG. 8 illustrates a mechanism for sending requests REQ from a terminal to a transponder. This mechanism, which is usual per se, is usually permanently implemented in a terminal but is, according to the described embodiments, only implemented atblock 47. - As soon as it is powered on and in operation, the transponder read-write terminal starts (block 60, ST) after a turn-on, initialization, and test phase, a standby procedure during which it waits for a communication to be established with at least one transponder. This procedure essentially comprises periodically sending (block 47) a polling sequence (REQ) to transponders that may be present in the field of the terminal. By implementing the embodiment of
FIG. 6 , this request sending 47 is only performed once the fact that the transponder is in contact with the terminal has been validated. After each sending of apolling request 47, the reader monitors (block 62, ATQ?) the reception by its demodulator of a response message ATQ from a transponder which would have entered its field. In the absence of a response, the reader loops onto the sending of apolling 47. When it receives a response ATQ, it passes to a mode where it is checked that the transponder actually is a transponder intended for it as well as to a possible anti-collision mode (block 63) to individualize the transponders in its field. - Various embodiments have been described, various alterations, modifications, and improvements will occur to those skilled in the art. In particular, the dimensions to be given to the resistors in the implementation of the variations and the values of the limiting currents and of the different thresholds, as well as the periodicity of the measurements and iterations, depend on the application and more specifically on the transponder family to which a given transponder is dedicated. Further, the inequality relations may correspond to strict or non-strict inequalities. Further, the practical implementation of embodiments is within the abilities of those skilled in the art based on the functional indications given hereabove, by using the hardware and software tools usually present in terminals. It should be noted that the implementation of these embodiments requires no modification of the transponder and is only performed on the reader side.
- Such alterations, modifications, and improvements are intended to be part of this disclosure, and are intended to be within the spirit and scope of the present invention. Accordingly, the foregoing description is by way of example only and is not intended to be limiting. The present invention is limited only as defined in the following claims and the equivalents thereto.
Claims (8)
1. A method for protecting communication between an electromagnetic transponder and a terminal, wherein the transmission of a polling request by the terminal is only allowed when the transponder is in mechanical contact or in quasi-mechanical contact with a terminal package, the package including a communication antenna.
2. The method of claim 1 , wherein:
a) a first value of the current in an oscillating circuit of the terminal is periodically measured;
b) a second value of a ratio between a no-load value of this current, stored when no transponder is in the field of the terminal, and the first value, is calculated;
c) said second value is compared with a third value of said ratio calculated in a previous iteration; and
d) as long as the second and third values are not equal, steps a to c are repeated.
3. The method of claim 2 , wherein, in case the second and third values are equal:
e) the second value is compared with a threshold;
the sending of a request is allowed if this threshold has not been reached;
g) it is returned to step a) if this threshold has been exceeded.
4. The method of claim 3 , wherein if said threshold has been reached, the sending of the request is preceded by an increase in the value of a resistive element of the oscillating circuit if the second value is greater than 2.
5. The method of claim 2 , wherein if the second value is smaller than the third one, the possible transmission of a request is blocked.
6. The method of any claim 2 , wherein:
step b) is preceded by a comparison of the first value with the no-load value; and
in case of an identity, it is returned to step a), or
in the opposite case, it is proceeded to step c).
7. A terminal for communicating with an electromagnetic transponder, comprising means capable of implementing the method of claim 1 .
8. A cell phone comprising the terminal of claim 7 .
Applications Claiming Priority (3)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
FR1154863A FR2976104B1 (en) | 2011-06-03 | 2011-06-03 | SECURING COMMUNICATION BETWEEN AN ELECTROMAGNETIC TRANSPONDER AND A TERMINAL |
FR1154863 | 2011-06-03 | ||
PCT/FR2012/050844 WO2012164180A1 (en) | 2011-06-03 | 2012-04-18 | Securing a communication between an electromagnetic transponder and a terminal |
Publications (2)
Publication Number | Publication Date |
---|---|
US20140118115A1 true US20140118115A1 (en) | 2014-05-01 |
US9507975B2 US9507975B2 (en) | 2016-11-29 |
Family
ID=46146929
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US14/123,751 Active 2033-01-16 US9507975B2 (en) | 2011-06-03 | 2012-04-18 | Protection of communication between an electromagnetic transponder and a terminal |
Country Status (4)
Country | Link |
---|---|
US (1) | US9507975B2 (en) |
EP (1) | EP2715607B1 (en) |
FR (1) | FR2976104B1 (en) |
WO (1) | WO2012164180A1 (en) |
Cited By (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US9344156B2 (en) | 2011-06-03 | 2016-05-17 | Stmicroelectronics (Rousset) Sas | Protection of communication by an electromagnetic transponder |
US9356656B2 (en) | 2011-06-03 | 2016-05-31 | Stmicroelectronics (Rousset) Sas | Assistance for positioning a transponder |
US9407307B2 (en) | 2011-06-03 | 2016-08-02 | Stmicroelectronics (Rousset) Sas | Transponder positioning aid |
US9507975B2 (en) | 2011-06-03 | 2016-11-29 | Stmicroelectronics (Rousset) Sas | Protection of communication between an electromagnetic transponder and a terminal |
US9508033B2 (en) | 2009-06-19 | 2016-11-29 | Stmicroelectronics (Rousset) Sas | Power management in an electromagnetic transponder |
Families Citing this family (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US10164600B2 (en) * | 2015-10-12 | 2018-12-25 | Nxp B.V. | NFC or RFID device RF detuning detection and driver output power regulation |
Citations (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20100068999A1 (en) * | 2006-11-27 | 2010-03-18 | Joakim Bangs | Near field rf communicators and near field rf communications-enabled devices |
US20100282849A1 (en) * | 2008-01-03 | 2010-11-11 | Nxp B.V. | Transponder detection by resonance frequency reduction |
US20100291871A1 (en) * | 2008-01-23 | 2010-11-18 | Innovision Research & Technology Plc | Near field rf communicators |
US20100328026A1 (en) * | 2009-06-25 | 2010-12-30 | Stmicroelectronics (Rousset) Sas | Authentication of an electromagnetic terminal-transponder couple by the transponder |
US20140113692A1 (en) * | 2011-06-03 | 2014-04-24 | Stmicroelectronics (Rousset) Sas | Transponder positioning aid |
Family Cites Families (57)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPH08191259A (en) | 1995-01-11 | 1996-07-23 | Sony Chem Corp | Transmitter-receiver for contactless ic card system |
FR2757952B1 (en) | 1996-12-27 | 1999-03-19 | Gemplus Card Int | RADIO TRANSPONDER PROVIDED WITH AN ANTENNA AND A FREQUENCY TUNING CIRCUIT |
GB2321725A (en) | 1997-01-30 | 1998-08-05 | Motorola Inc | Apparatus and method for dissipating excess power received by a contactless portable data carrier |
DE69717782T2 (en) | 1997-02-05 | 2003-09-18 | Em Microelectronic Marin Sa | Base station of a remote control system with voltage-controlled and phase-controlled oscillator |
EP0999517B1 (en) | 1998-11-03 | 2003-06-04 | EM Microelectronic-Marin SA | Rechargable active transponder |
FR2787655B1 (en) | 1998-12-21 | 2001-03-09 | St Microelectronics Sa | CAPACITIVE MODULATION IN AN ELECTROMAGNETIC TRANSPONDER |
FR2792135B1 (en) | 1999-04-07 | 2001-11-02 | St Microelectronics Sa | VERY CLOSE COMPLAGE OPERATION OF AN ELECTROMAGNETIC TRANSPONDER SYSTEM |
US6650226B1 (en) | 1999-04-07 | 2003-11-18 | Stmicroelectronics S.A. | Detection, by an electromagnetic transponder reader, of the distance separating it from a transponder |
FR2792130B1 (en) | 1999-04-07 | 2001-11-16 | St Microelectronics Sa | ELECTROMAGNETIC TRANSPONDER WITH VERY CLOSE COUPLING OPERATION |
FR2792132B1 (en) | 1999-04-07 | 2001-11-02 | St Microelectronics Sa | READING TERMINAL OF AN ELECTROMAGNETIC TRANSPONDER OPERATING IN VERY CLOSE COUPLING |
FR2792134B1 (en) | 1999-04-07 | 2001-06-22 | St Microelectronics Sa | DISTANCE DETECTION BETWEEN AN ELECTROMAGNETIC TRANSPONDER AND A TERMINAL |
FR2792137A1 (en) * | 1999-04-07 | 2000-10-13 | St Microelectronics Sa | DETECTION, BY AN ELECTROMAGNETIC TRANSPONDER READER, OF THE DISTANCE THAT SEPARATES IT FROM A TRANSPONDER |
FR2792136B1 (en) | 1999-04-07 | 2001-11-16 | St Microelectronics Sa | DUPLEX TRANSMISSION IN AN ELECTROMAGNETIC TRANSPONDER SYSTEM |
US7049935B1 (en) | 1999-07-20 | 2006-05-23 | Stmicroelectronics S.A. | Sizing of an electromagnetic transponder system for a dedicated distant coupling operation |
FR2796781A1 (en) | 1999-07-20 | 2001-01-26 | St Microelectronics Sa | DIMENSIONING OF AN ELECTROMAGNETIC TRANSPONDER SYSTEM FOR HYPERPROXIMITY OPERATION |
FR2796782A1 (en) | 1999-07-20 | 2001-01-26 | St Microelectronics Sa | SIZING OF AN ELECTROMAGNETIC TRANSPONDER SYSTEM FOR DEDICATED OPERATION IN REMOTE COUPLING |
FR2804557B1 (en) | 2000-01-31 | 2003-06-27 | St Microelectronics Sa | ADAPTING THE TRANSMISSION POWER OF AN ELECTROMAGNETIC TRANSPONDER DRIVE |
DE10004922A1 (en) | 2000-02-04 | 2001-08-09 | Giesecke & Devrient Gmbh | Transponder for fitting to a contactless chip card receives energy from a high frequency alternating field via an antenna and voltage formed by a rectifier acting as a command variable to a clock generator with a frequency adjuster. |
FR2808946A1 (en) | 2000-05-12 | 2001-11-16 | St Microelectronics Sa | VALIDATION OF THE PRESENCE OF AN ELECTROMAGNETIC TRANSPONDER IN THE FIELD OF A READER |
FR2808941B1 (en) | 2000-05-12 | 2002-08-16 | St Microelectronics Sa | VALIDATION OF THE PRESENCE OF AN ELECTROMAGNETIC TRANSPONDER IN THE FIELD OF AN AMPLITUDE DEMODULATION READER |
FR2808945B1 (en) | 2000-05-12 | 2002-08-16 | St Microelectronics Sa | EVALUATION OF THE NUMBER OF ELECTROMAGNETIC TRANSPONDERS IN THE FIELD OF A READER |
FR2808942B1 (en) | 2000-05-12 | 2002-08-16 | St Microelectronics Sa | VALIDATION OF THE PRESENCE OF AN ELECTROMAGNETIC TRANSPONDER IN THE FIELD OF A PHASE DEMODULATION READER |
FR2812986B1 (en) | 2000-08-09 | 2002-10-31 | St Microelectronics Sa | DETECTION OF AN ELECTRIC SIGNATURE OF AN ELECTROMAGNETIC TRANSPONDER |
US20030169169A1 (en) | 2000-08-17 | 2003-09-11 | Luc Wuidart | Antenna generating an electromagnetic field for transponder |
US6944424B2 (en) | 2001-07-23 | 2005-09-13 | Intermec Ip Corp. | RFID tag having combined battery and passive power source |
DE10148830B4 (en) | 2001-10-04 | 2005-10-06 | Texas Instruments Deutschland Gmbh | Method and system for authenticating a first transceiver to a remotely located second transceiver |
EP1445877B1 (en) | 2002-11-13 | 2006-05-24 | STMicroelectronics S.A. | Communication between electromagnetic transponders |
DE10259384B3 (en) | 2002-12-18 | 2004-05-13 | Siemens Ag | Battery charge level detection device for mobile data carrier e.g. for use in identification system, using measurement of charging time of auxiliary capacitor |
US7975926B2 (en) | 2003-12-26 | 2011-07-12 | Semiconductor Energy Laboratory Co., Ltd. | Paper money, coin, valuable instrument, certificates, tag, label, card, packing containers, documents, respectively installed with integrated circuit |
GB2413195A (en) | 2004-04-17 | 2005-10-19 | Hewlett Packard Development Co | A memory tag and reader with password protection of tag memory |
US8451089B2 (en) * | 2004-06-15 | 2013-05-28 | Nxp B.V. | Radio identification with an additional close-range check |
FR2873243A1 (en) | 2004-07-13 | 2006-01-20 | St Microelectronics Sa | ADAPTABLE POWER CIRCUIT |
DE102004039401A1 (en) | 2004-08-13 | 2006-03-09 | Siemens Ag | Transceiver transponder system |
KR20070076071A (en) | 2006-01-17 | 2007-07-24 | 삼성전자주식회사 | Contactless card and contactless card system |
US20080079542A1 (en) | 2006-09-26 | 2008-04-03 | Broadcom Corporation, A California Corporation | Radio frequency identification (RFID) carrier and system |
US20080129509A1 (en) | 2006-11-30 | 2008-06-05 | Symbol Technologies, Inc. | RFID interrogations of system components in RFID systems |
KR100853190B1 (en) | 2006-12-08 | 2008-08-20 | 한국전자통신연구원 | Apparatus for managing power of passive tag and method thereof |
US7992779B2 (en) | 2007-09-10 | 2011-08-09 | Mastercard International, Inc. | Method for use in association with identification token and apparatus including identification token |
JP5174424B2 (en) | 2007-10-24 | 2013-04-03 | デクセリアルズ株式会社 | Antenna circuit, resistance reduction method thereof, and transponder |
WO2009105115A2 (en) | 2008-02-22 | 2009-08-27 | T-Mobile Usa, Inc. | Data exchange initiated by tapping devices |
WO2009138687A2 (en) | 2008-04-30 | 2009-11-19 | Stmicroelectronics (Rousset) Sas | Detection of a variation in distance relative to an axis of rotation |
US8564413B2 (en) | 2008-04-30 | 2013-10-22 | Stmicroelectronics (Rousset) Sas | Recharge of an active transponder |
AU2009302900B2 (en) | 2008-10-10 | 2016-03-03 | Implantica Patent Ltd. | Charger for implant |
US8482412B2 (en) * | 2008-10-16 | 2013-07-09 | The Boeing Company | Data interface process with RFID data reader glove |
FR2947073A1 (en) | 2009-06-19 | 2010-12-24 | St Microelectronics Rousset | ENERGY MANAGEMENT IN AN ELECTROMAGNETIC TRANSPONDER |
FR2947074A1 (en) | 2009-06-19 | 2010-12-24 | St Microelectronics Rousset | INDUCTIVE EVALUATION OF THE COUPLING FACTOR OF AN ELECTROMAGNETIC TRANSPONDER |
FR2947075A1 (en) | 2009-06-19 | 2010-12-24 | St Microelectronics Rousset | RESISTIVE EVALUATION OF THE COUPLING FACTOR OF AN ELECTROMAGNETIC TRANSPONDER |
FR2947364A1 (en) | 2009-06-25 | 2010-12-31 | St Microelectronics Sas | AUTHENTICATION OF A TERMINAL-ELECTROMAGNETIC TRANSPONDER COUPLE BY THE TERMINAL |
FR2947362A1 (en) | 2009-06-25 | 2010-12-31 | St Microelectronics Sas | AUTHENTICATION OF A TERMINAL BY AN ELECTROMAGNETIC TRANSPONDER |
JP5278197B2 (en) | 2009-06-29 | 2013-09-04 | ソニー株式会社 | Non-contact communication device and non-contact communication method |
FR2960993A1 (en) | 2010-06-03 | 2011-12-09 | St Microelectronics Rousset | EVALUATION OF THE COUPLING FACTOR OF AN ELECTROMAGNETIC TRANSPONDER WITH CAPACITIVE DISAGGREGATION |
FR2968802B1 (en) | 2010-12-10 | 2014-05-23 | St Microelectronics Rousset | CONTACTLESS COMMUNICATION WITH HUMAN CONTACT AUTHORIZATION AND VISUAL INDICATOR |
FR2968801B1 (en) | 2010-12-10 | 2013-08-23 | St Microelectronics Rousset | CONTACT WITHOUT CONTACT WITH AUTHORIZATION BY HUMAN CONTACT |
FR2976105B1 (en) | 2011-06-03 | 2013-05-17 | St Microelectronics Rousset | SECURING COMMUNICATION BY AN ELECTROMAGNETIC TRANSPONDER |
FR2976104B1 (en) | 2011-06-03 | 2013-11-15 | St Microelectronics Rousset | SECURING COMMUNICATION BETWEEN AN ELECTROMAGNETIC TRANSPONDER AND A TERMINAL |
FR2976102B1 (en) | 2011-06-03 | 2013-05-17 | St Microelectronics Rousset | ASSISTING THE POSITIONING OF A TRANSPONDER |
FR2980608B1 (en) | 2011-09-28 | 2013-09-06 | St Microelectronics Rousset | OPTIMIZATION OF THE PROCESSING SPEED BY AN ELECTROMAGNETIC TRANSPONDER |
-
2011
- 2011-06-03 FR FR1154863A patent/FR2976104B1/en not_active Expired - Fee Related
-
2012
- 2012-04-18 WO PCT/FR2012/050844 patent/WO2012164180A1/en active Application Filing
- 2012-04-18 EP EP12722431.9A patent/EP2715607B1/en active Active
- 2012-04-18 US US14/123,751 patent/US9507975B2/en active Active
Patent Citations (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20100068999A1 (en) * | 2006-11-27 | 2010-03-18 | Joakim Bangs | Near field rf communicators and near field rf communications-enabled devices |
US20100282849A1 (en) * | 2008-01-03 | 2010-11-11 | Nxp B.V. | Transponder detection by resonance frequency reduction |
US20100291871A1 (en) * | 2008-01-23 | 2010-11-18 | Innovision Research & Technology Plc | Near field rf communicators |
US20100328026A1 (en) * | 2009-06-25 | 2010-12-30 | Stmicroelectronics (Rousset) Sas | Authentication of an electromagnetic terminal-transponder couple by the transponder |
US20140113692A1 (en) * | 2011-06-03 | 2014-04-24 | Stmicroelectronics (Rousset) Sas | Transponder positioning aid |
Cited By (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US9508033B2 (en) | 2009-06-19 | 2016-11-29 | Stmicroelectronics (Rousset) Sas | Power management in an electromagnetic transponder |
US9344156B2 (en) | 2011-06-03 | 2016-05-17 | Stmicroelectronics (Rousset) Sas | Protection of communication by an electromagnetic transponder |
US9356656B2 (en) | 2011-06-03 | 2016-05-31 | Stmicroelectronics (Rousset) Sas | Assistance for positioning a transponder |
US9407307B2 (en) | 2011-06-03 | 2016-08-02 | Stmicroelectronics (Rousset) Sas | Transponder positioning aid |
US9507975B2 (en) | 2011-06-03 | 2016-11-29 | Stmicroelectronics (Rousset) Sas | Protection of communication between an electromagnetic transponder and a terminal |
Also Published As
Publication number | Publication date |
---|---|
EP2715607B1 (en) | 2019-06-05 |
US9507975B2 (en) | 2016-11-29 |
WO2012164180A1 (en) | 2012-12-06 |
FR2976104B1 (en) | 2013-11-15 |
EP2715607A1 (en) | 2014-04-09 |
FR2976104A1 (en) | 2012-12-07 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
US9507975B2 (en) | Protection of communication between an electromagnetic transponder and a terminal | |
JP5539056B2 (en) | Resistance evaluation of coupling coefficient of electromagnetic transponder | |
JP5668196B2 (en) | Inductivity evaluation of coupling coefficient of electromagnetic transponder | |
JP5668197B2 (en) | Power management in electromagnetic transponders | |
JP5501871B2 (en) | Terminal authentication by electromagnetic transponder | |
US8446259B2 (en) | Authentication of an electromagnetic terminal-transponder couple by the transponder | |
EP3588792A1 (en) | Reducing power consumption for connection establishment in near field communication systems | |
US8907761B2 (en) | Authentication of an electromagnetic terminal-transponder couple by the terminal | |
US8798533B2 (en) | Evaluation of the coupling factor of an electromagnetic transponder by capacitive detuning | |
JP2009044713A (en) | System, method, and computer program product for automatically adjusting modulation index of wireless high performance device reader | |
EP3461018B1 (en) | Method and system for operating a communications device that communicates via inductive coupling | |
US9098788B2 (en) | Optimization of the processing speed of an electromagnetic transponder | |
EP3337051B1 (en) | Method and system for operating a communications device that communicates via inductive coupling | |
US9407307B2 (en) | Transponder positioning aid | |
US9356656B2 (en) | Assistance for positioning a transponder | |
US6879246B2 (en) | Evaluation of the number of electromagnetic transponders in the field of a reader | |
US9344156B2 (en) | Protection of communication by an electromagnetic transponder | |
CN112771784B (en) | System and method for device coexistence | |
KR102140570B1 (en) | Radio Frequency Identification System |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
AS | Assignment |
Owner name: STMICROELECTRONICS (ROUSSET) SAS, FRANCE Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:WUIDART, LUC;REEL/FRAME:036557/0773 Effective date: 20131205 |
|
STCF | Information on status: patent grant |
Free format text: PATENTED CASE |
|
MAFP | Maintenance fee payment |
Free format text: PAYMENT OF MAINTENANCE FEE, 4TH YEAR, LARGE ENTITY (ORIGINAL EVENT CODE: M1551); ENTITY STATUS OF PATENT OWNER: LARGE ENTITY Year of fee payment: 4 |